When rabbit peritoneal neutrophils were exposed to Bacteroides products, the neutrophils released N-acetyl-β-glucosaminidase, a lysosmal enzyme. Bacteroides products also induced directional locomotion (chemotaxis) of rabbit PMN neutrophils in Boyden chambers. The chemotactic response of rabbit neutrophils was dependent on the dosages of Bacteroides stimulant.

The enzyme release response was greatly enhanced when Bacteroides products were pre-incubated at 37°C for 30 minutes with equal volumes of fresh guinea pig complement. However, when Bacteroides outer membrane or sterile culture supernatants were pre-incubated with fresh guinea pig compliment, PMN neutrophil chemotaxis was retarded.

Lactate dehydrogenase (a cytoplasmic marker) was not released upon exposure of rabbit PMN neutrophils to Bacteroides products. This indicated that the response to Bacteroides products reflect an active extracellular secretion of PMN neutrophil lysosmal contents rather than a non-specific discharge of enzymes as a result of cell (PMN neutrophil) death.

These findings suggest an altered inflammatory response to neutrophils during the interaction of Bacteroides with the host defense mechanism.